When your linkpoint account is created you receive linkpoint welcome
email which contains username, password and the certificate in the PEM
format. You need to convert this certificate from PEM to P12 format. One
way to do this is to run the following from a command prompt:

AVS: AVS stands for Address Verification Service.
It can be used as an additional layer of protection for merchants who wish
to verify that the purchaser knows the billing address of the cardholder
(in case these are two different people). This is not a very serious form
of risk mitigation or fraud prevention, and yet it does give some assurance
that a hacker isn't simply generating a list of valid credit card numbers
and purchasing product at will.
AVS simply matches the numeric portion of the cardholder's street billing address
and the 5 or 9-digit zip code of the cardholder's billing address.
The AVS request parameters are STREET and ZIP. The processing network verifies
the AVS information, comparing a portion of the billing address from the request
message with address data on file at the VIC or the issuer's center. Based on
the comparison, a response will be returned which confirms whether the information
matches or not. Banks do not decline transactions based on the AVS check. The AVS
response is returned as two single tab-delimited characters: YY, NN, YN, NY
(Y-'matches', N for 'does not match'). This information is just an advice.
However, the H-Sphere system will either allow or decline the transaction
depending on the selected AVS status. AVS is available only for US cardholders.Important:
To provide non US cardholders CC processing, disable AVS check-up in the merchant gateway configuration.

Test Mode:
- FALSE: credit card transactions will be completed and credit cards will be charged;
- TRUE: authorization requests will be sent for verification without
settlement requests and credit cards won't be charged.
* In Test Mode, all transactions appear to be processed as real transactions.
The gateway accepts the transactions, but does not pass them on to the financial institutions.
Accordingly, all transactions will be approved by the gateway when Test Mode is turned on.

Click Submit Query

In Edit Gateway, select the newly created connection and press Edit.

Note the two new parameters that appeared on the gateway configuration page, Key File, and Certificate File.
Put the key and certificate files on the control panel server to the locations suggested here.